If you grow cilantro, let it go to seed, the next year you will have 20x as much without planting.
Amen! It is right up there with purslane, catnip, and dill for reseeding itself.
We have way more come up than we know what to do with; a lot of it gets tilled, just to keep it more less in bounds. We really don’t use much of it; instead, we let it go to seed, as we go through a lot of coriander in our cooking & preserving.
I don’t do cilantro. My herb garden wound up not having much light, since hubby never got around to cutting down the trees that block the morning sun, and it’s on the North East side of the house. I have some chives that manage to hang on for a while, and that’s about it.